Egg trays and incubator trays as well as trays used in the baking industry and elsewhere are generally formed of metallic or plastic materials. In order to recycle such trays and maintain them in a clean sanitary condition, they must be washed from time to time. However, most plastic and metallic materials are hydrophobic with the result that washing liquids tend to cling to the articles in the form of droplets instead of spreading out in a thin film for ready evaporation. It is therefore particularly difficult to dry plastic or metallic trays after washing and the duration of any conventional drying operation employed is materially prolonged. As a result, the drying step in the conveyor system unduly delays the unit cycle time of the entire system.
It is, of course, common practice to remove water from clothing, liquid slurries and other materials by centrifuging operations using a perforated drum into which the material to be dried is charged as exemplified by U.S. Pat. Nos. 930,898 and 3,300,871. However, such equipment is not adapted for use in drying plastic or metal trays or containers. In particular such equipment is not capable of use with a conveyor for supplying and removing articles to be dried.
Previous methods of drying these trays include a high speed blower for exposing the trays to hot air, but this system was quite time consuming and required a considerable output of energy to both heat the air and run the blower. The present invention therefore accomplishes not only a shortening of the drying cycle time but also substantially decreases energy consumption.